WHAT’S UP HIS SLEEVES? Jets defensive coordinator Mike Pettine faces the daunting task of rallying his unit after the loss of All-Pro cornerback Darrelle Revis to a torn ACL, which leaves the inconsistent Antonio Cromartie as the team’s No. 1 corner.Bill Kostroun

WHAT’S UP HIS SLEEVES? Jets defensive coordinator Mike Pettine faces the daunting task of rallying his unit after the loss of All-Pro cornerback Darrelle Revis to a torn ACL, which leaves the inconsistent Antonio Cromartie as the team’s No. 1 corner. (Bill Kostroun)

Darrelle Revis had not had an MRI exam yet, so the diagnosis of a season-ending ACL tear in his left knee had not been delivered, but Pettine already assumed the worst. He began talking to his fellow coaches, trying to figure out what adjustments his defense would need to make without its best player.

“That’s the world of the NFL,” Pettine said. “There’s no sympathy cards in the mail. Every week is a short one, other than your bye week. We needed to move on. That’s the approach we took.”

Pettine, head coach Rex Ryan and defensive backs coach Dennis Thurman have all coached together since their days on the Ravens staff. The trio is extremely close and it is on them to make the adjustments necessary to survive L.A.R.

“There’s nobody that can just step in and replace Darrelle Revis,” Pettine said. “We’re not foolish enough to just think we can continue to do what we’ve been doing. But we have some pretty good players in that room, as well. I think a lot of people take the knee-jerk reaction of the sky is falling and they lost their best player. We have some really good players in that room and some really prideful guys as well. To replace somebody like that, it’s you ask everybody to step up.”

People should not expect the Jets defense to suddenly morph into a different look. Pettine said the changes will be subtle and probably will not be picked up by the casual observer.

The Jets still will base their defensive game plan each week around the team they are playing. The problem for them now is they will no longer be able to place Revis on the opponent’s best receiver and then figure out the rest.

“The game plan changes each week,” Pettine said. “I’ve used the analogy before: We’re custom tailors and we’re making a suit each week. We have to build a plan based on two things: the opponent and what they do and then what do we have available from our perspective.”

Ryan has done his best this week to convince the team that losing Revis does not mean the season is over. As great a player as Revis is, the Jets have 13 games left on the schedule and can’t wallow in self pity.

As for this week, Ryan said it has been business as usual for him. He attended defensive meetings Wednesday and offensive yesterday.

“We do [game planning] collectively like we always do,” Ryan said. “We’ve been down this road before. I remember in Baltimore we had our fourth corner as our first corner. We’ve had to overcome some injuries before. We know how to do it … obviously, not with somebody of that caliber.”

Pettine said the Jets have an “inventory” of defensive packages they look at each week and pick certain portions of that inventory to use based on their opponent. Without Revis, there are some calls the Jets will no longer use, but Pettine said it’s not as if they’re going to the Tampa 2 style of defense to give their cornerbacks help on every play.

A key to the defense will be cornerback Antonio Cromartie, who slides into Revis’ role as the No. 1 corner. Cromartie is as inconsistent as he is talented, which leads to lapses. Against the Dolphins last week, he shut down Brian Hartline for nearly the entire game, but then gave up a 41-yard pass to him in overtime.

“As we all know, when Cro is dialed in he can be as good as there is in the game,” Pettine said. “That’s his challenge. He knows it. It didn’t even need to be said.”

The Jets played without Revis for two games in 2010, when he had a pulled hamstring and two weeks ago against the Steelers when he had a concussion.

“We’ve gone through this before,” Pettine said. “This isn’t something that’s never happened before and we’re unprepared for. He’s a great player and he will be missed, but our mindset is we have to move on. It’s full-speed ahead.”